RVF Flatspot 5k-7K

[Mark-091]

Need help guys! Cnt get flat spot on my NC35 to disappear. I replaced standard exhaust system for a full Tyga one with 450mm carbon can, I'm running stock airbox setup incl OEM filter, have tried these settings :

1.5/8 set air screw, stock needles with RO HRC springs and 115 main jets.

Then I tried the same as above only this time I replaced the standard washers under the needles with 1mm ones.

It just seems the same, the bike pulls well up to 5k, hits Flatspot (stutters) and then as soon as it gets past 7k it pulls very strongly right up to the red line. Carbs where balanced before I removed the standard exhaust.

Are flatspots caused by being too lean or too rich and what should I try nxt.

Could it be down to a standard cdi or does it not effect this.

Appreciate any advice.

[CRM]

how was it before you changed the pipe ?
did you check the float heights ? do a search i used an old plastic business card to make a height tool for both the 30/35 and it makes checking heights a doddle.
i found a single MM can make quite a difference.
i also found using the non genuine filter and the copy exaggerated the midrange dip.
i would leave the needle heights well alone, keep them as standard, and try a 110/112r jetting setup and see how you get on.
if i recall my RVF with a yamamoto was running 112 all round and i got it pulling like the clappers with no flat spots.

[Neosophist]

Ignition box shouldn't alter it.

Is your airbox and filter standard?

The flatspot can be caused by either but is usually too lean (a dyno with a fuel/air sensor will be able to confirm)

Are all your carb pieces in the correct way?

What did you set the float heights too?

[Mark-091]

Thanks for the quick replies, yea running genuine filter and also Checked float heights they are all standard, i will check them again using ur method CRM just to make sure. I will also try the standard washers and the smaller jet sizes to see how I get on, but will have to order sum for rick, is ther anywhere else I can get sum, was ur Yammoto a half system? I would lyk to get the settings as close as possible before taking it to a dyno. They seem to be rebuilt correctly with no leaks or flooding jst annoying flat spot.

Thanks again for the advice guys.

[CRM]

yes it was a half system, if it was running fine with stock pipe, small increments each time and note the settings with each change.
no better dyno than your bum - on paper my RVF was making good power, but i got better settings with around 20 - 30 strips and rebuilds before i got it perfect
Just hope your carb rubbers are new - if they are not, buy some, it will save loads of time and stress

[Mark-091]

Yea was running perfect factory setup, yea will write it all down, do u happen to
Kno what everything was set at when u finished her? I didn't replace the carb rubbers just all the seals in the carbs, they have been goin on and off easy enough, will these not being new affect the mixture?

[CRM]

which seals in the carbs did you replace ?
i cant remember honestly i think its currently 112 all round i ended up with and standard washer. it was the float heights that made the biggest difference for me. using the card method allows you to check both sides at the same time and if one side is out - well they need to be equal. you cant do this easily with a ruler / eye

[Le_Blur]

viewtopic.php?f=22&t=26178&hilit=business+card

This is the post you're after.

[Mark-091]

Just o-rings etc in all of the carbs Honda genuine parts. Thanks for the link to the post. I think that the 115s all
Round are jst too big since looking at other posts in the workshop section. Cnt wait to try CRM's setup to see how she goes. Suppose there shouldn't be much difference in flow between a half yammoto and full tyga system. On the tyga website it says they increased the main jet by one size. I kno it depends on where the bike is being used as to how it runs but does anybody kno what they mean by one size? What increments do the standard jets go up in?

[spongy.bob]

What increments do the standard jets go up in?

003 or 002, so they go 110, 112, 115, 118, 120.....and so on.

I stand to be corrected but nc35 standard jets are 108 aren't they? So tyga used 110?

Having said that the Makuni jets I have seem to go up in 2.5 intervals.